Substances in Common Use — Science STD 9 — Question
Maharashtra BoardEnglish MediumSTD 9ScienceSubstances in Common Use3 Marks
Question
What is meant by radioactivity?
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Answer
Elements with a high atomic number such as uranium, thorium, radium have a property of spontaneously emitting invisible, highly penetrating and high energy radiation.
This property is called radioactivity.
A substance having this property is called a radioactive substance.
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